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From: Andrew Morton <akpm@linux-foundation.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] fs: use mapping_set_error instead of opencoded set_bit
Date: Tue, 13 Sep 2016 14:29:44 -0700	[thread overview]
Message-ID: <20160913142944.fcb0067c66924a14be92b6dc@linux-foundation.org> (raw)
In-Reply-To: <20160913065259.GA31898@dhcp22.suse.cz>

On Tue, 13 Sep 2016 08:53:01 +0200 Michal Hocko <mhocko@kernel.org> wrote:

> On Mon 12-09-16 15:18:23, Andrew Morton wrote:
> > On Mon, 12 Sep 2016 15:11:46 -0700 Andrew Morton <akpm@linux-foundation.org> wrote:
> > 
> > > > @@ -409,7 +408,7 @@ static int afs_write_back_from_locked_page(struct afs_writeback *wb,
> > > >  		case -ENOMEDIUM:
> > > >  		case -ENXIO:
> > > >  			afs_kill_pages(wb->vnode, true, first, last);
> > > > -			set_bit(AS_EIO, &wb->vnode->vfs_inode.i_mapping->flags);
> > > > +			mapping_set_error(wb->vnode->vfs_inode.i_mapping, -ENXIO);
> > > 
> > > This one is a functional change: mapping_set_error() will rewrite
> > > -ENXIO into -EIO.  Doesn't seem at all important though.
> > 
> > hm, OK, it's not a functional change - the code was already doing
> > s/ENXIO/EIO/.
> 
> Yes the rewrite is silent but I've decided to keep the current errno
> because I have no idea whether this can change in future. It doesn't
> sound probable but it also sounds safer to do an overwrite at a single
> place rather than all over the place /me thinks.

Well, this is the only place in the kernel where we attempt to set
anything other than EIO.  I do think it's better to be honest about
what's happening, right here at the callsite.

WARNING: multiple messages have this Message-ID
From: Andrew Morton <akpm@linux-foundation.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] fs: use mapping_set_error instead of opencoded set_bit
Date: Tue, 13 Sep 2016 14:29:44 -0700	[thread overview]
Message-ID: <20160913142944.fcb0067c66924a14be92b6dc@linux-foundation.org> (raw)
In-Reply-To: <20160913065259.GA31898@dhcp22.suse.cz>

On Tue, 13 Sep 2016 08:53:01 +0200 Michal Hocko <mhocko@kernel.org> wrote:

> On Mon 12-09-16 15:18:23, Andrew Morton wrote:
> > On Mon, 12 Sep 2016 15:11:46 -0700 Andrew Morton <akpm@linux-foundation.org> wrote:
> > 
> > > > @@ -409,7 +408,7 @@ static int afs_write_back_from_locked_page(struct afs_writeback *wb,
> > > >  		case -ENOMEDIUM:
> > > >  		case -ENXIO:
> > > >  			afs_kill_pages(wb->vnode, true, first, last);
> > > > -			set_bit(AS_EIO, &wb->vnode->vfs_inode.i_mapping->flags);
> > > > +			mapping_set_error(wb->vnode->vfs_inode.i_mapping, -ENXIO);
> > > 
> > > This one is a functional change: mapping_set_error() will rewrite
> > > -ENXIO into -EIO.  Doesn't seem at all important though.
> > 
> > hm, OK, it's not a functional change - the code was already doing
> > s/ENXIO/EIO/.
> 
> Yes the rewrite is silent but I've decided to keep the current errno
> because I have no idea whether this can change in future. It doesn't
> sound probable but it also sounds safer to do an overwrite at a single
> place rather than all over the place /me thinks.

Well, this is the only place in the kernel where we attempt to set
anything other than EIO.  I do think it's better to be honest about
what's happening, right here at the callsite.


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  reply	other threads:[~2016-09-13 21:32 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-30 17:28 [PATCH -v2] mm: Don't use radix tree writeback tags for pages in swap cache Huang, Ying
2016-08-30 17:28 ` Huang, Ying
2016-08-30 18:29 ` Rik van Riel
2016-08-31  9:14 ` Mel Gorman
2016-08-31  9:14   ` Mel Gorman
2016-08-31 15:17   ` Huang, Ying
2016-08-31 15:17     ` Huang, Ying
2016-08-31 15:39     ` Mel Gorman
2016-08-31 15:39       ` Mel Gorman
2016-08-31 15:44       ` Huang, Ying
2016-08-31 15:44         ` Huang, Ying
2016-08-31 21:35       ` Andi Kleen
2016-08-31 21:35         ` Andi Kleen
2016-08-31 21:30   ` Andrew Morton
2016-08-31 21:30     ` Andrew Morton
2016-09-01  8:51     ` Mel Gorman
2016-09-01  8:51       ` Mel Gorman
2016-09-01  9:13     ` Michal Hocko
2016-09-01  9:13       ` Michal Hocko
2016-09-12 11:16       ` [PATCH 0/2] do not squash mapping flags and gfp_mask together (was: Re: [PATCH -v2] mm: Don't use radix tree writeback tags for pages in) Michal Hocko
2016-09-12 11:16         ` Michal Hocko
2016-09-12 11:16         ` [PATCH 1/2] fs: use mapping_set_error instead of opencoded set_bit Michal Hocko
2016-09-12 11:16           ` Michal Hocko
2016-09-12 22:11           ` Andrew Morton
2016-09-12 22:11             ` Andrew Morton
2016-09-12 22:18             ` Andrew Morton
2016-09-12 22:18               ` Andrew Morton
2016-09-13  6:53               ` Michal Hocko
2016-09-13  6:53                 ` Michal Hocko
2016-09-13 21:29                 ` Andrew Morton [this message]
2016-09-13 21:29                   ` Andrew Morton
2016-09-12 11:16         ` [PATCH 2/2] mm: split gfp_mask and mapping flags into separate fields Michal Hocko
2016-09-12 11:16           ` Michal Hocko
2016-09-12 11:48           ` Michal Hocko
2016-09-12 11:48             ` Michal Hocko

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